A leading rights group has urged the U.S. and Libya to clarify the legality of a surprise extradition of a suspect in the 1988 bombing of Pan Am Flight 103 over Lockerbie, Scotland.

Libyan officials say a powerful militia was involved in the clandestine detention and questioning of a suspect in the 1988 downing of a New York-bound PanAm flight over Lockerbie, Scotland.

A former Libyan intelligence official accused of making the bomb that brought down Pan Am Flight 103 over Lockerbie, Scotland, in 1988 has appeared in federal court in Washington to face charges of international terrorism.

The announcement that a Libyan man suspected in the 1988 bombing of a passenger jet has been taken into U.S. custody put the spotlight back on the notorious terrorist attack.

The Justice Department says a Libyan intelligence official accused of making the bomb that brought down Pan Am Flight 103 over Lockerbie, Scotland, in 1988 in an international act of terrorism has been taken into U.S. custody and will face federal charges in Washington.

WASHINGTON – The Justice Department announced new charges Monday against a Libyan bombmaker in the 1988 explosion of Pan Am Flight 103 over Lockerbie, Scotland, an attack that killed 259 people in the air and 11 on the ground. But it nonetheless represents one of the more consequential counterterrorism announcements from the Trump administration Justice Department. “At long last, this man responsible for killing Americans and many others will be subject to justice for his crimes," Barr said. The New York-bound Pan Am flight exploded over Lockerbie less than an hour after takeoff from London on Dec. 21, 1988. Besides Barr, another key figure in the Lockerbie investigation was Robert Mueller, who was the Justice Department’s criminal chief at the time the first set of charges was announced.

FILE - In this Dec. 22, 1988, file photo police and investigators look at what remains of the nose of Pan Am 103 in a field in Lockerbie, Scotland. The Justice Department expects to unseal charges in the coming days in connection with the 1988 bombing of a Pan Am jet that exploded over Lockerbie, Scotland, killing 270 people, according to a person familiar with the case. (AP Photo/Martin Cleaver, File)WASHINGTON – The Justice Department plans to unseal new charges in the coming days in connection with the 1988 bombing of a Pan Am jet that exploded over Lockerbie, Scotland, killing 270 people, according to a person familiar with the case. We will not rest until all those responsible are brought to justice,” Barr said at a 1991 news conference announcing the charges. The New York-bound flight exploded over Lockerbie less than an hour after takeoff from London on Dec. 21, 1988.

FILE - In this Dec. 22, 1988, file photo police and investigators look at what remains of the nose of Pan Am 103 in a field in Lockerbie, Scotland. The Justice Department expects to unseal charges in the coming days in connection with the 1988 bombing of a Pan Am jet that exploded over Lockerbie, Scotland, killing 270 people, according to a person familiar with the case. (AP Photo/Martin Cleaver, File)WASHINGTON – The Justice Department plans to unseal new charges in the coming days in connection with the 1988 bombing of a Pan Am jet that exploded over Lockerbie, Scotland, killing 270 people, according to a person familiar with the case. We will not rest until all those responsible are brought to justice,” Barr said at a 1991 news conference announcing the charges. The New York-bound flight exploded over Lockerbie less than an hour after takeoff from London on Dec. 21, 1988.